1. Technical Field
The present invention relates to the field of video display optics, and more particularly to color correction techniques used with display optics.
2. Description of the Related Art
LCOS display systems incorporate a high pressure lamp and a light engine for generating a video display in lieu of a cathode ray tube found in traditional video displays. The light engine receives ultra bright light from the high pressure lamp and processes the light through display optics contained within the light engine. Display optics are typically provided for each of the base colors, namely red, green and blue. Variations between the display optics tend to cause color non-uniformity in the LCOS displays. For example, the green optics of a particular LCOS light-engine may be slightly more transmissive in the top left corner. This would produce a green zone in the top left corner of the displayed image. Other LCOS light-engines can have non-uniform zones in other areas of the display. The degree and nature of color non-uniformity varies tremendously from light-engine to light-engine. Notwithstanding, color non-uniformity also changes as a function of pixel brightness. Hence the color non-uniformity can vary as the brightness level of video changes.
Color non-uniformity correction has been implemented to address color non-uniformity in LCOS displays, however current implementation requires substantial processing resources to implement color non-uniformity correction. Color non-uniformity correction is typically performed after frame rate doubling and gamma correction have been applied to a video signal. To perform color non-uniformity correction after frame rate doubling results in the color non-uniformity correction being applied to twice as much data as contained in an original video signal. Further, gamma correction increases the size of the video data. Hence, performing color non-uniformity correction after gamma correction further increases the amount of video data that must be processed.
On the other hand, applying color non-uniformity correction prior to frame rate doubling and gamma correction creates an even greater obstacle. Color non-uniformity correction typically increases the amount of video data contained in a video signal as well. However, the frame rate doubler is limited with respect the amount of video data that can be processed. Thus a “bit bottleneck” is created and video data incorporating color non-uniformity correction cannot be adequately processed by the frame rate doubler. Even if the color non-uniformity corrected video could be adequately doubled, the amount of video data handled by the rest of the processing components would be increased. Thus, a need exists for a method and system for color non-uniformity correction prior to increasing the frame rate that overcomes the problems described above.